28 PHYSA ANCILLARIA. 



OBSERVATIONS. 



"The spire of this species is unusually short, 

 truncated at tip like the Paludina decisa, and 

 the suture is so inconspicuous as to give rise to 

 the name which I have chosen for it. My 

 brother, Mr. B. Say, obtained it in the Dela- 

 ware river near Easton, and Mr. Jessup col- 

 lected numerous specimens in the Connecticut 

 river above Hartford. It may be distinguished 

 from P. heterostropha, by the shorter and trun- 

 cated spire, inconspicuous suture, as well as by 

 the more obtusely rounded junction of the la- 

 brum with the base, and by the general form." 

 — Say. 



The very few specimens I have seen from the 

 Connecticut river, (figs. 1 and 2,) have a more 

 solid texture than those which inhabit the Dela- 

 ware, (figs. 3 — 8,) but it is most probable that 

 they constitute but one species. 



I am indebted to Mr. Anthony for the speci- 

 men of "P. Sayi," (fig. 9,) and find it agrees 

 in the very deep fold, and other characters, with 

 a shell (fig. 10) from a branch of the Schuyl- 

 kill, which I refer to P. ancillaria. 



